Grinding wheel dressing mechanism



May 20, 1952 S. P. BRUCE GRINDING WHEEL DRESSING MECHANISM 3Sheets-Sheet 1 Filed April 29, 1947 fts`- .I

INVENTOR.

May 20, 1952 s. P. BRUCE GRINDING WHEEL DRESSING MECHANISM 3Sheets-Sheet 2 Filed April 29, 1947 INVENTR. fazz'orJ Pfuce. BY

May 20, 1952 s. P. BRUCE GRINDING WHEEL DRESSING MECHANISM 3Sheets-Sheetl 5 Filed April 29. 1947 .m Re. 0C 5 W M, m www Patented May20, 1952 Stanford P. Bruce; Detroit, Micha. assig'nor to Wfheel TrueingTool Company, Detroit,-Micl1.,v a corporation of Delaware ApplicationApril 29, 1947-, Seriali-Nor 744,744?

(Cl. I25--1-L) 8 Claims. l.

Thisv invention relates to new and useful improvementsin tool holders ofthe type conventionally usedl for dressing `grinding Wheelsv and'. thelike;

All grinding wheels mustr be dressed from. time tof time asthey cuttingfaces become Worn.'` in order tok maintain a proper cutting. action.Dressing usually is accomplished by moving ai diamond back and forthacross the periphery of they wheel asvthelatter is rotated aboutitsaxis.Th'ediamond is mounted'in a suitable holder which holdsv it `steady andat arv proper angle: to the Wheel and suitable means may be provided forrotating the holder periodically to prev-ent the diamond Vfrom WorkingclearancesI necessary for rotationY of the diamond holder frequentlypermit the rotatableparts to chatter or vibrate; and.` when this occursthesurface of the: grinding wheelis left roughand. unl'ltforaccurateWork.. All eiforts to arrange the partsof the dressing' mechanismA insuchV manner that the diamond holder" canI be rotatedf without'.attendant destructive chattering have for'the most'part beenunsuccessful. This problem is a Very real! one and hasA long beenreco'gnizedby workers: in the art.

In.y certain standardi grinding machines. such as Cincinnati grinders;the dressing mechanism: is mountedI in a conned' spacebehindlthegrinding Wheel; In this case, the problem ofi providingrotation without vibration is`- further c'orn'pli'cated by the fa'ctthattheV diamond holder" must.v be mounted-.and operated a limited spa'ceiAnL important object ofi' the present invention is 1 to'- provide` adressing.v mechanism for grinding Wheels` wherein the` diamondf holderis mounted for rotation an'd inA suchy manner thatv chatteringor-vibration is substantially entirelyf elimina'ted'.

`Another obj eotLof; the invention is tol'provide. a

w-.heel dressing mechanism? of the above menvide: afwheel dressing:mechanism? that isv-siniplef in construction, eflicient` in operationand?` re1- ativelyz inexpensive to manufacture.

Otherfobjects andadvantages. ofrth'e'Y invention will beapparent duringthe' course.- of fthe -following description.

2 In theY drawing forming. a part of this speciiicationand'wherei'nzlike numerals are employed to'v designate like4 .partsthroughout the same:

Fig; liis a.. fragmentary end elevational view of a conventional..grinding machiney havingl a wheel dressing mechanism embodying thepresent inventio'n.associated therewith, parts of the grinder being.broken; away andshown in section for clearof illustration; Eig. 2,:isant enlarged view of the portion of Fig.. L enclosed in the-'circlefZ-gparts being shown 'ini eievation'and parts iny section to'v more clearlyillustrate the Working parts of the Wheel dressing mechanism; Y I YFig.; 3fs an,enlargedxfragmentarm longitudinal 'sectionaloview taken.onthe line'A 3-31 of Fig. 2;

Fig; Llisa' fragmentary'perspective view of a portionfor thegrindingwheel anditsadjuncts and particularly illustrating: a preferredmeans for imparting intermittent or step-by-step rotation'toftheidiamondiholder Fig.; v5isranenlarged, fragmentary, verticalsectional view taken on the line 5*-5 of Fig.` 4;

Fig. 61is-.a1fragmentary, longitudinal sectional v-iev. throughthefwheelf dressing. mechanism;

Eig- .7^ is a fragmentary.- transversesectional View taken on the'line-"ll-ofFig. 6;

Fig'. S'is. affragmentary, longitudinal sectional View: throughamodified Wheel dressing mechanis'mf. embodying they invention;v andl 9;is: a-` transverse sectional View taken on the".V lin'e: 9;'-9` of Fig;8.

In? theJ` drawing, the wheel. dressing mechanism l.ei'nbodyingf the'present invention is shown associated with a Cincinnati grinder vofthetype having; a rotatably` driven grinding wheel I0 shielded .bya'rgua'rd l2; Behind-'theguardz- I2 is au generally horizontal table l4which supports theA usual slide' I6: forV` recprocator-y movementparallel toY the a-Xis: of grinding Wheel Il). Slide It carries.y asWheel' dressing. mechanismL which extends forwardly through the guardl2Vto -position.E ai diamond'A nilo-:iny operative association withtheewo'rking' face or periphery of the grinding Wheel I0.

The' above set-up is f conventional and= isA given merely to provides`an operativeI setting: for? the wheeldressing:mechanism;- oftheipresentK invention. A Cincinnati typefgrinderwassselected because itis .typical of thoseigrinders Whichv allow onlyfslight espace-atoradjacent t'o l"the surface of the. wheel' inv which the-wheeldressing-*mechanism must-operate. By`l reasonV ofv the' unique mannerinWhich'zthepartsare combinedand corelated; the mechanism of thisinvention; is=ad mirably-suited for. grinders of theCincinn'ati type.

In this connection, however, it is to be understood that the wheeldressing mechanism is not limited in its use to grinders of the typehere shown. It can be adapted readily for any type of grinder, and itcan be used in any capacity where a. device of this character hasutility.

Considered in certain of its broader aspects, the wheel dressingmechanism embodying the present invention comprises a carrier I8 whichis adapted for attachment to the slide I6 and rotatably mounts the toolholder 20. As best shown in Fig. 2, carrier I8 forms a case whichencloses the rear portion of tool holder 20, andy the latter projectsforwardly from the end of said carrier toward the grinding wheel I0. Adiamond tool 22 set into a socket 23 provided in the forward end of theholder 20 carries the usual diamond 24, and the slide I6 is advanced orretracted in the conventional manner to position the diamond for properengagement with the peripheral face of grinding wheel II) when saidslide I6 is within that portion of its traversing movement whichcorresponds with the width of said peripheral face of the grindingwheel.

In the form of the invention shown in Figs. 1-7, intermittent,step-by-step rotation is imparted to the holder 2B by a ratchet 26 whichis mounted on the projecting forward portion of the holder and extendsradially beyond the carrier I8 for engagement with an actuator or pawl28 on the guard I2. When the slide I6 is moved in one direction on tableI4 during the dressing operation, ratchet 26 is pushed against the pawl28 and the latter rotatably actuates the ratchet and its adjuncts. Asbest shown in Figure 4, the ratchet 26 is actuated by pawl 28 secured toguard I2 at the completion of the traverse of the dressing tool acrossthe face of the grinding wheel and while the dressing tool is out ofcontact with the grinding wheel. When the slide I6 is retracted, pawl 28passes freely over the teeth of the ratchet 26.

In this manner, step-by-step rotation is imparted to the tool holder 20and after each operation of the slide the diamond 24 presents a fresh,sharp cutting edge to the grinding wheel I0. Since ratchet 26 is rotatedcontinuously in the same direction, the diamond 24 is worn evenly andits working life is substantially extended.

Preferably, a detent mechanism also is provided for controlling rotativemovement of the tool holder 20 and for preventing the pawl 28 frominadvertently rotating ratchet 26 in a reverse direction.

More specifically, the carrier I8 comprises a generally circular case3l) having a suitable cover 32 fastened thereto by an annular series ofscrews 34 or the like. A rearwardly extending shank 36 is formed on thecase 30, which shank enters a socket 38 in the end of slide I6 and issecured b y a set screw 40. Thus, the carrier I8 is xably l associatedwith the slide I6 and is movable therewith as the latter slides back andforth on the table I4.

The case 36 and cover 32 define a generally circular chamber 42 withinthe carrier I8 and the tool holder 20 extends into the chamber through acentral opening 44 in the cover. At the rearward end'thereof, the toolholder 20 is formed with a radially extending, annular flange 46which'seats solidly against the rear face of chamber 42 and ts snuglywithin the annular surrounding wall of the chamber. It will be observedthat the front radial face of flange 46 is spaced from the front wall ofchamber 42 and that an annular spring element 48 is confinedtherebetween. The spring element 48 here shown is an annular, undulatingstrip of spring metal which engages the flange 46 and cover 32 atcircumferentially spaced points, as shown in Fig. 3; and this elementnormally is compressed to yieldably force the holder 20 rearwardlyagainst the carrier I8. A washer 50 preferably is interposed betweenflange 46 and the spring 4I.

From the foregoing, it will be readily apparent that chamber 42 providesa broad flat surface behind the tool holder 20 and that the latter ispressed solidly against this surface by the spring 48. Also, the annularsurrounding wall of the chamber snugly fits the periphery of flange 46to additionally support and stabilize the holder 20. In actual practice,I have found that this unique combination and correlation of parts iseiiicacious to prevent destructive vibration or chattering of the toolholder 20 in the carrier I8 during the critcal dressing operation; and,at the same time, the tool holder is free to rotate in the carrier.Thus, by reason of the instant construction, I am able to mount the toolholder for rotation; and, at the same time, have eliminated thedestructive chattering and vibration which heretofore has inevitablyaccompanied a rotatable mounting.

It is desirable to position the rear bearing surface of the tool holder20 as close to the diamond point 24 as possible in order to reduce theeffect of such minor vibration as may occur. Further, it is desirablethat the assembly as a whole be compact in order that it may be usedwith grinders such as the Cincinnati grinder shown in the drawing.

Ratchet 26 conveniently may be fastened to the tool holder 20 by aradial set screw 52 (Fig. 2) and it preferably is disposed against andsupported by the carrier I8. The pawl 28 is in the form of an elongatedbar which is hinged to a support 54, as best shown in Fig. 4. One end ofsupport 54 is pivoted to a mounting block 56 on the guard I2 and theother end thereof is pivoted to a linkage 58, which linkage also isattached to the mounting block 56 and is adjustable to effect a properengagement between the pawl and ratchet 26. As shown in Fig. 5, thesupport 54 carries a stop 60 which extends along one side of the pawl 28and prevents the same from swinging in one direction about its pivots.

Thus, when the wheel dressing mechanism is moved in one direction, onthe table I4, pawl 28 is positioned by stop 6D to engage the teeth ofratchet 26 so as to rotate the tool holder 20 and diamond tool 22.However, on the return stroke of the dressing mechanism, pawl 28 pivotsfreely to substantially the dotted line position in Fig. 5, in whichposition it rides over the teeth of ratchet 26 without rotating thesame. In this manner,

Y ratchet 26 and its adjuncts are continuously ropawl and ratchetmechanism hereinabove described causes the ball detent 64 to move fromone socket 68 to the adjacent socket, and succesandere `sive operationsof the 'meehanism causes 'the {ba-11 V'detei'it to move progressivelyfrom 'one socket 'to another. In Jthis manner, the diamond 24 is idenfroy ting the to'olrholder 2|). AIn 'this form 'of the invention, thevto'olholder v2l] is provided with a rearwardly extending hub 1o and the here-2a which receives the diamond t'ool 272 'extends 'enyirely through the"hbtlder. Th'e 'chamber 42 'in carrier 'is "is farmed 'with'a 'centrallymated re- ;c'ss 'or :a socket 1'4 'which Vaccomniodates the hub and theshank '36 is'formedfseparate1yas perfiiarrge'swhih nts snugly `ih socketr4 and abuis therear face "of the holder 20. Also, 'shank :i6 is Yformed'with an Yaxially extending centrally 1ocated head 18whi`chprbjects'forwardly of flange "It Aandseats snugly inthe bore `23tosupport the 'rear lporti'onfofthe 'tool holder v2l) for rotation.

Fixed on the hub T0 a 'ratchet 80 'which 'coacts with apawl 82 to rotatethe t'oo'l holder "20. If'desired, theratch'etll may be a separateelement on the tool holder, but it preferably is formed integrallytherewith vlas shown in Fig. 9. l'Ailso,-it will be observed that inthis v.form of the invention, the pawl 82 is carried by a plunger-84which is slidably mounted in the carrier I8 and is arrangedvtangentially to the ratchet 80. A spring -86 ahead of plunger 84 urgesthe latter iormally to a retractedposition i-n the 'carrier i8. At one`Aend of the plunger 84 Tis a longitudinal Asl'xanliz 88 Whichprojectsfrom the carrier "F8 for :actuation by suitable stop or abutment (not1sh`ow'n)., yas will be readily understood Aby those skilled intlieart.

inoperation, the-latter form 'of the invention is substantiallyidentical to` the form first described andthe-same advantages obtain inboth 'forms of the invention. When slide 1.6 is moved vin one-di-/r'e'etlcnr on the table I4., the :shank 88 engages a vsuitably.positioned stop or ab'utment advance ftheplunger 84 and move pa'Wl"8`2against lratchet A"80. "On -the return stroke. of 'slide l6,fs'pring 86"T aiitdx-riaticfally retracts the .plun'ger 84 "and pawl 82. "Thepartsthen occupy the initial .position and are ready for another cycle ofoperation. Each time the pawl and ratchet mechanism operate's,-thediamond 24 is'turned angularly to pre- -se'nt fa fresh sharplfcutt-ing'edge to the grinding wheel l0.

It is to be understood that the forms of the invention herewith shownand described are to be taken as preferred examples of the same and thatvarious changes in the size, shape and arrangement of the parts may beresorted to Without departing from the spirit of the invention or thescope of the appended claims.

il C.

6 holder having a radially projecting, annular flange; 'a earrier'forsaid holder shaped to provide a "seat'for the rear radial surface ofsaid 'fiange and having' an annular surrounding surtface around the"periphery of said flange, said annular 'surface having a plurality A'ofcircumferentially spaced sockets; detent means carried by said lflangeand projecting radially therefrom to seatsuccess'ively insaid socketsupon rotation vof theto'ol holder; spring means about said holder urgingsaidiiange pressed solidly against its seat;

-'andratchetmeans on said holder for rotating the 'toolho'ld'er insaid'carrier.

"2. The combination as set vforth in claim 1 Whereinsaid 'springmea'riscomprises an annular undulating 'stripfof spring metal confinedloet'Weenthe forward radial face of the' flange 'and C'all'elt A3. `In agrinding wheel dressing assembly, a rotatable Atool holder having aradially projecting, 'annular harige; a carrier for 'said holder havinga 'seat "for 'the rear radial surface of said flange 'and an `annularsurface around the vperiphery of said iange, said 'annular surfacehaving aplu- 'rality of 'circumfe'rentially `spaced sockets; detentmeans*carried Yby said ange and projecting lradially 'therefrom to seatsuccessively in said 'sockets 'upon'r'otation of the tool holder; springmeans about said holder holding said flange pressed solidly against itsseat; Y'a ratchet fixed "onthe tool'holder'; a slide 'on which thecarrier and its adjuncts 'are reciprocated 'in a direction parallel "tothe plane of said ratchet; and vastationary'paivlmountedatene end ofthereciproca- 'tory'travel'of said 'carrier to engage the ratchet duringreciprocation of the 4carrier and adapted t'o 'impart a s'tep-by-steprotation to the tool holder.

4. VIn a grinding wheel dressing assembly, a Vrotai'able tool holderShaving a radially project- 'i-ng Vannular flange.; a carrier for saidholder hav- 'ing a se'at Afor the rear radial surface of said flange andan 'annularsurfacearound the periphe'ry of 'said wflange, 'said annularsurface having a plurality of circumferentially spaced sockets,dterit'ineans 'carried' by Said flange vand project- 'in'g radiallytherefrom to seat successively in said socliet'suponrotation ofth'e'tool holder; spring means about said holder holding said flangepressed Lsolidly against its Seat; a ratchet fixed 4on the tool'holderand projecting radially beyond the c'ar'rie'r; afslide onwhich thecarrier is bodily reciprocated in a direction transverse to 'the raxisof said ratchet; and'astationary pavvl positioned at -one end of thereciprocatory travel of said carrier 'to engage said ratchet duringreciprocation ofthe carrier whereby to impart a step-bystep rotation 4tos'aid t'o'ol holder.

`l5. ln combination, `a`machine grinder having a lrotatably drivengrinding Wheel; and a Wheel dressing mechanism Vmounted for 'translatorymovement 'parallel to a'surf'ace of the grinding wheel to be dressed,said Wheel dressing mechanism including a rotatable tool holder having aradially projecting annular flange, a carrier for said holder having aseat for the rear radial surface of said flange and an annular surfacearound the periphery of said flange, said annular surface having aplurality of circumferentially spaced sockets, detent means carried bysaid flange and projecting radially therefrom to seat successively insaid sockets upon rotation of the tool holder, spring means holding saidange pressed solidly against the seat, a ratchet xed on the tool holderand projecting radially beyond the carrier, and a stationary pawlpositioned at an end of said translatory movement to engage said ratcheteach time relative bodily movement occurs between the wheel dressingmechanism and said grinding wheel, whereby automatically to impart astep-by-step rotation in one direction to said tool holder.

6. In a grinding wheel assembly including a wheel rotatably mountedabout its axis, a guard around said wheel, a slide mounted forreciprocation along said guard in a line of traverse parallel to theaxis of said wheel and across the peripheral face thereof, said slidebeing also mounted for advancement toward and retraction away from saidperipheralA face and having a forward end facing and proximate to saidperipheral face when said slide is advanced and is within that portionof its traversing movement corresponding to the width of said peripheralface, a holder for a diamond tool on said slide mounted for rotationabout its axis and projecting from said forward end of said slide towardsaid peripheral face with its axis intersecting said peripheral face, acarrier on said slide rotatably supporting said tool holder, saidcarrier and tool holder having lcooperating abutting surfaces to sustaina thrust load imposed axially of said tool holder, and an indexingmechanism for effecting incremental rotation of said tool holderincluding means operatively connected to said holder to rotate the sameand a member relatively fixedly positioned in said assembly in the pathof movement of said slide near an end of its traverse and actuating saidmeans upon engagement therewith to operate the same and thereby rotatesaid tool holder through an increment of rotation.

'7. In a grinding wheel assembly including a wheel rotatably mountedabout its axis, a guard around said wheel, a slide mounted forreciprocation along said guard in a line of traverse parallel to theaxis of said wheel and across the peripheral face thereof, said slidebeing also mounted for advancement toward and retraction away from saidperipheral face and having a forward end facing and proximate to saidperipheral face when said slide is advanced and is within that portionof its traversing movement corresponding to the width of said peripheralface, a holder for a diamond tool on said slide mounted for rotationabout its axis and projecting from said forward end of said slide towardsaid peripheral face with its axis intersecting said peripheral face, acarrier on said slide rotatably supporting said tool holder, saidcarrier and tool holder having cooperating abutting surfaces to sustaina thrust load imposed axially of said tool holder. and an indexingmechanism for effecting incremental rotation of said tool holderincluding a stop member relatively iixedly positioned in said assemblyin the path of movement of said slide and means operatively connected tosaid holder to rotate the same upon contact with and 8 actuation by saidstop member, such contact occurring when said slide is at an end of itstraversing movement and while the diamond tool is beyond an edge of saidperipheral face and therefore out of contact therewith.

8. In a grinding wheel assembly including a. wheel rotatably mountedabout its axis, a guard around said wheel, a slide mounted forreciprocation along said guard in a line of traverse parallel to theaxis of said wheel and across the peripheral face thereof, said slidebeing also mounted for advancement toward and retraction away from saidperipheral face and having a forward end facing and proximate to saidperipheral face when said slide is advanced and is within that portionof its traversing movement corresponding to the width of said peripheralface, a holder for a diamond tool on said slide mounted for rotationabout its axis and projecting from said forward end of said slide towardsaid peripheral face with its axis intersecting said peripheral face, acarrier on said slide rotatably supporting said tool holder, saidcarrier and tool holder having cooperating abutting surfaces to sustaina thrust load imposed axially of said tool holder, and an indexingmechanism for effecting incremental rotation of said tool holderincluding a ratchet operatively connected to said holder and a memberrelatively xedly positioned in said assembly in the path of movement ofsaid slide and actuating said ratchet upon engagement therewith toeffect incremental rotation of said tool holder.

STANFORD P. BRUCE.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 249,003 Cherry Nov. 1, 1881631,640 Hubbuch Aug. 22, 1899 1,001,303 Reeves Aug. 22, 1911 1,105,854Shriver Aug. 4, 1914 1,127,888 Heys Feb. 9, 1915 1,428,744 Bastian Sept.12, 1922 1,508,939 Reeves Sept. 16, 1924 1,731,719 Kempton et al Oct.15, 1929 1,908,626 Ford May 9, 1933 1,997,551 Romaine Apr. 9, 19352,178,875 Kearns Nov. 7, 1939 l2,187,544 Laessker Jan. 16, 19402,252,892 Kottman Aug. 19, 1941 2,443,929 Patterson June 22, 19482,505,684 McClernon Apr. 25, 1950 2,505,685 McClernon Apr. 25, 1950FOREIGN PATENTS Number Country Date 494,704 Great Britain Oct. 31, 1938

